The proper conditioning of the soil about growing plants requires that the soil conditioners such as fertilizer be supplied to the root system slowly, steadily and evenly over a long period of time. A single sudden application of fertilizer, for example, may shock the plant, expose the root system to burning, deprive the plant of nutrients as it matures and weaken it against blight and insect attacks.
Various schemes have been devised for feeding plants by means of the slow disintegration of fertilizer sticks or cartridges. In these prior systems, the rate at which the fertilizer is released is predetermined principally by the geometry and other characteristics of the stick or cartridge. Because the user is unable to control the release rate, the amount of fertilizer applied to the soil over a given period is often incompatible with the needs of the plant. In addition, many known devices do not provide for the even distribution of the nutrients and other soil conditioners about the plant and root system but instead can provide only for localized soil treatment. Moreover, none of the known plant feeders is capable of controlling weed growth and the amount of water reaching the plant roots.